WRT45GC Port Forwarding Lockup

Ok, I've had this router for a while now and have noticed this issue before but never really bothered to ask about it. Under Applications & Gaming>Port Range Forwarding, when trying to add an 8th custom port forwarding entry, the router seems to kinda lock up and not add the new entry. I've heard about a beta firmware but any links I found with it are dead. Anyone else know how to solve this issue?